Japanese Unexamined Patent Application Publication No. 2005-134831 has proposed an image forming device, which has a removing port, through which a developing unit can be removed from the image forming device. In the image forming device, a belt unit that is located as opposed to the developing unit is held by a cover (access door) for opening and closing the removing port. It is possible to improve efficiency of a replacing operation of the developing unit by removing the belt unit away from the developing unit by opening the cover.
More specifically, this device is a so-called intermediate transfer type color image forming device. A transfer medium storage box for storing sheets therein is disposed on the bottom of a housing of the image forming device. A plurality of image forming units are disposed above the transfer medium storage box. The plurality of image forming units are for a plurality of different developer colors (yellow, magenta, cyan and black), respectively. Each image forming unit has a photosensitive drum, an exposing unit, and a developing unit. These image forming units are stacked in a laminated manner in the order of yellow, magenta, cyan and black from below. An intermediate transfer member (belt unit) is disposed as opposed to each color photosensitive drum. Color developer images formed on the photosensitive drums are sequentially transferred to the intermediate transfer member. A multicolor image formed on the intermediate transfer member by superimposing toner images of each color is transferred on a sheet by a transfer mechanism, thereby forming a desired image on the sheet.
The intermediate transfer member is held by the access door. For this reason, the intermediate transfer member is usually opposed to the photosensitive drums. When the access door is opened, the intermediate transfer member is displaced together with the access door from its original position, and the space in front of the photosensitive drums is opened. By retreating the intermediate transfer member from the space in front of the photosensitive drums in this manner, the photosensitive drums are exposed to the outside. Accordingly, the photosensitive drums and the developing units can be easily taken out from the housing of the image forming device, thereby improving operability of replacement of the developing units and operability of maintenance work.
U.S. Pat. No. 5,953,564A has proposed an image display unit provided with a cleaning mechanism for cleaning a transfer belt. This device is configured so as to scrape off toner remaining on the transfer belt by use of a cleaning brush or a cleaning blade. The scraped remaining toner is conveyed by a toner conveying mechanism to a waste toner box.